Recent studies from our laboratory have shown that infusion of ATP following release of 30 minutes of bilateral renal artery occlusion accelerated the recovery of post ischemic renal failure. We now plan to extend the ligation of renal arteries to 60 minutes and determine if ATP would have any salutary effect on renal function following this period of ischemica. Infusion of ATP to animals in shock will be carried out to determine if this would reverse the ultrastructural changes which are produced during shock. ATP will also be infused in dogs to determine if the ST segment depression which is produced by ligation of the left descending coronary artery would be reversed. Infusion of ATP will also be carried out in rats following a period of hepatic ischemia to determine if infusion of the compound would have any beneficial effects on liver function and survival of animals. The effect of insulin on muscle plasma membrane of animals in shock labelled with spin labels will be investigated to determine if there is any membrane conformation change produced during circulatory shock which is responsible for the observed tissue insulin resistance.